Drive device for agricultural harvestors

ABSTRACT

The drive device for an agricultural harvester includes a gear unit (5) driven by an internal combustion engine through a hydrostatic transmission comprised of a hydraulic pump (1) and a hydraulic motor (2). The transmission unit (5) drives a pair of drive wheels (12) through the differential (8). A power takeoff device (13) is installed between the hydraulic motor (2) and the transmission unit (5) and a clutch is installed between the power takeoff device (13) and the transmission unit (5) thus permitting operation of the power takeoff device while power to the drive wheels is disconnected. A brake (4) is provided on the transmission unit and a brake is provided for each of the drive wheels (12).

TECHNICAL FIELD

This invention relates to a drive device for agricultural harvesterswhich includes a power takeoff upstream of a transmission unit and aclutch downstream of the power takeoff and upstream of the transmissionunit.

BACKGROUND OF THE INVENTION

The Vogel Technical Book series "Agricultural Engineering" titledEncyclopedia of Agricultural Engineering, by Robert Fritz Kuntze (FirstEdition, 1987) on pages 70 and 71 describes drive trains for combines inwhich power is conveyed from an internal combustion engine (dieselengine), via a hydraulic pump, to a hydraulic motor, which acts on thedriving wheels of the agricultural harvester via at least one gear unit.Information on brakes and drives for further devices of the agriculturalharvester cannot be found in this prior art.

Great Britain patent GB-A-912, 109 shows a tractor drive train for thedrive wheels which includes a differential having a decoupling feature.

U.S. Pat. No. 2,158,483 shows two power takeoff shafts at right anglesto one another and driven by an angular gear unit.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the invention to create a drive device for anagricultural harvester that is simply constructed in terms of design andprovides a problem-free drive for further devices of the agriculturalharvester.

This object is achieved by use of a power takeoff in the drive train forthe driving of further devices of the agricultural harvester. A clutchis provided downstream of the power takeoff by which the drive to thedriving wheels can be engaged or disengaged. This arrangement has theadvantage that only a single drive (prime mover) is required both forthe driving of the agricultural harvester itself and also for furtherdevices of the harvester. The power takeoff is provided so that thisdrive can operate in problem-free fashion, a clutch being arranged inthe drive train downstream of the power takeoff, with which clutch thedrive to the driving wheels can be engaged or disengaged so that thedrive of the harvester can be operated independently of the furtherdevices and/or the other way around. Thus it is conceivable, forexample, that the further devices are still driven while the movement ofthe harvester is halted, so that the processing operation taking placein the harvester can continue. This structure, moreover, has theadvantage that a commercially available transmission must besupplemented only by the power takeoff and the clutch, so that the drivedevice according to the invention also represents an economicalsolution. Since commercially available and standard transmissions havebeen proven in practical applications, the supplementation according tothe invention is also simple in terms of design and is problem-free.

In development of the invention, in order to enhance the efficiency, aclutch is placed downstream of the power takeoff by which the furtherdevices can be engaged or disengaged. The supplementation of such aclutch has the advantage that the drive possibilities are augmentedbecause, first, the drive to the driving wheels can be engaged ordisengaged and, second, the drive for the further devices of theharvester can be engaged or disengaged. In this way, depending on theoperating conditions of the agricultural harvester, the possibilitiesexist that both the driving wheels and also the further devices aredriven, that only the driving wheels or only the further devices aredriven, or that the driving wheels are halted and also the furtherdevices are disengaged so that the prime mover is in a quasino-loadcondition.

In development of the invention, the clutch arranged in the drive trainis made as a non-positively operating clutch and/or the clutch arrangedupstream of the further devices is made as a positively operatingclutch. This has the advantage that the individual components (drive ofthe driving wheels and drive of the further devices) can be optimallyengaged in the drive train or disengaged from the drive train, dependingon their design features and their intended purpose, so that the mostwear-free operation possible is insured for these components.

In development of the invention, the power takeoff is made as an angulargear. In this way, a power takeoff is obtained that operates inproblem-free fashion and is simple to realize in terms of design.Furthermore, this angular gear is easy to integrate in the substantiallylongitudinally extending drive device (in particular, beneath anoperator cab of the agricultural harvester), which is located in theregion of the drive axis, and permits direct driving of the furtherdevices.

In development of the invention, the prime mover is an internalcombustion engine (preferably diesel engine) having a downstreamhydraulic pump that drives a hydrostatic transmission. This combinationhas the advantage that it has been proven in practice and represents ahydrostatic drive with which the driving (speed) of the harvester can beeasily varied, so that costly change gears become unnecessary.Furthermore, the arrangement of the power takeoff in the drive train hasthe advantage that, upon a variation of the hydrostatic drive, whichresults in a change in the speed of the harvester, the processing speedof the further device is also adapted to the travel speed of theharvester. On the other hand, it is possible to let the further devicescontinue to run, for example when the machine is halted, so that theprocessing operation continues with the machine halted. At least onegear unit can also be positioned downstream of the power takeoff in thedirection of the further device. Further power takeoffs, furtherclutches or flywheels can also be attached here.

In further development of the invention, the drive from the prime movermay be reversed in its rotation direction at least briefly after theclutch arranged in the drive train is disengaged. This has the advantagethat after the drive of the harvester is disengaged, the drive of thefurther devices is reversed so that, for example in the case of amalfunction or plugging of one of the further devices, this malfunctionor plugging can be remedied by means of the reversal of rotationdirection. This can easily be initiated, for example, by an operator ofthe harvester pressing a button. It must be made certain, however, thatthe clutch located in the drive train is disengaged first before thereversal of rotation direction.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is illustrated schematically in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a drive device made according to the invention for anagricultural harvester. This drive device has a hydrostatic transmissionwhich includes a hydraulic pump 1 and a hydraulic motor 2, the hydraulicpump 1 being driven by an internal combustion engine, not illustrated.The hydraulic motor 2 drives a shaft 3 to which a parking brake 4 isconnected. The parking brake may be actuated when the harvester ishalted. A gear unit 5, which is made according to the invention as asimple reduction gear unit, is driven via the shaft 3. The output sideof this gear unit 5 includes a differential 8 driving a pair of jackshafts 6, on which service brakes 7 (for example disk brakes that can beactuated during the operation of the harvester) are arranged. Thedifferential allows unequal peripheral speeds of the driving wheels. Asis shown in FIG. 1, the shafts 6 drive a pair of simple reduction gearunits 9 which in turn drive shafts 10 on which the driving wheels, inthe form of rims 11 and tires 12, are arranged. In this way there iscreated a drive device for agricultural harvesters that has componentswhich have been proven in practice, operates reliably and can befabricated at low cost, especially in the mass production ofagricultural harvesters. According to the invention, this drive deviceis now supplemented in that a power takeoff in the form of an angulargear 13 is arranged in the drive train. Further, as can be recognized inFIG. 1, a clutch 14, which in particular operates in non-positivefashion, is assigned to the angular gear 13 in the drive train. Withthis clutch 14, the drive of the hydraulic motor 2 to the driving wheels(rims 11 and tires 12) can be engaged or disengaged. Downstream of theangular gear 13 there is a clutch 15, in particular acting in positivefashion, via which the further devices (not illustrated) can be engagedor disengaged. In this way, the drive of the agricultural harvester andthe drive of the further devices integrated in the agriculturalharvester can be driven independently or dependently according to theservice condition. In order to realize the most compact constructionpossible for the drive device made according to the invention, the powertake off (angular gear 13) is arranged in the immediate vicinity of thehydraulic motor 2 or on the hydraulic motor 2.

The drive device made according to the invention finds use inagricultural harvesters generally. A particular field of application iscombine harvesters, where the further devices of the combine harvesterare, for example, threshing, shaking, screening, cutting and pick-updevices. A further field of application is harvesters for forageprocessing, where the further devices are then cutting, conveying,processing, baling and discharge devices. Self-propelled large balers asharvesters can be cited as a third field of application, where thefurther devices are pick-up or baling and discharge devices for thelarge bales. The making according to the invention is obviously notrestricted to the three harvesters named but can also be extended tofurther fields of application (generally to agricultural or farmvehicles) and also to other types of agricultural harvesters (forexample field choppers).

What is claimed is:
 1. In a self-propelled harvester having an internalcombustion engine and a pair of driving wheels (11,12), a driving devicecomprising:a hydrostatic transmission includinga hydraulic pump (1)non-positively connected in driven relation to said internal combustionengine and a hydraulic motor (2) driven by said hydraulic pump (1), atleast one reduction gear unit (5); a first torque transmitting meansconnecting said hydraulic motor to said reduction gear unit, a secondtorque transmitting means between said one reduction gear unit and saiddriving wheels including a differential between said driving wheels, apower takeoff connected in driven relation to said first torquetransmission means and a main clutch in said first torque transmittingmeans between said one reduction gear unit and the connection betweensaid power takeoff and said first torque transmitting means, said mainclutch being operable to interrupt torque transmission to said onereduction gear unit.
 2. The harvester of claim 1 and further comprisingan auxiliary clutch (15) downstream of said auxiliary device by whichfurther devices may be engaged or disengaged.
 3. The harvester of claim2 wherein said main clutch is a non-positively acting clutch and saidauxiliary clutch is a positively acting clutch.
 4. The harvester ofclaim 1 wherein said power takeoff is a bevel gear (13).
 5. Theharvester of claim 1 and further comprising a parking brake (4)downstream of said main clutch (14) and upstream of said differential(8).
 6. The harvester of claim 5 and further comprising a wheel brake(7) for each of said driving wheels (11, 12).
 7. The harvester of claim1 and further comprising a wheel brake (7) for each of said drivingwheels (11, 12).